New Projects

July - August 1999

By joining Group Sponsored R&D Projects TWI Industrial Members gain access to substantial programmes at low cost, with the opportunity to steer work undertaken into areas of specific interest. The following GSPs have been, or are about to be, launched.

For a full list of proposed, active and closed projects see here

A simple fitness-for-purpose assessment procedure for corroded nozzles

Launch October 99, duration 1 year
Cost per sponsor £18 000 pa.
Project leader: A T Smith

Operational experience shows that pressure vessels can continue to perform satisfactorily despite being severely corroded. Pressure vessel components, such as nozzles, are particularly prone to loss of thickness because of the combined effects of environment and erosion. There is a need to assess whether such components can be considered fit-for-purpose in the corroded condition. Existing design procedures such as the area replacement rules of ASME VIII, the elastic stress analysis rules of BS 5500 and the design rules equations derived for the Welding Council all give widely varying limitations on the remaining wall thickness necessary to ensure structural integrity of nozzles.

This project aims to examine and adapt existing rules to develop a simple procedure to evaluate the fitness-for-purpose of corroded pressure vessel nozzle regions. It will evaluate failure criteria for corroded nozzles and validate the proposed simplified design procedures by comparison with model tests and finite element failure predictions.

Improvement to contact tip life and arc stability in continuous wire mechanised and robotic arc welding

Launch June 99, duration 2 years
Cost per sponsor £6 500 pa.
Project leader: G Melton

The contact tip (or tube) fitted to the welding torch plays a critical role in the economic operation of mechanised MIG, MAG and flux cored welding. Stable operation depends on the smooth feeding of wire and good electrical contact with the contact tip. Excessive wear can cause poor weld bead profile and misplacement, excessive spatter and eventually burn backs resulting in arc outage. The objectives of the study will be to gain a better understanding of tip wear mechanisms, to predict, and if possible, to extend contact tip life to improve weld quality and increase productivity by eliminating unscheduled maintenance shutdowns.

Barrikade^TM - fire resistant lightweight, affordable materials with no fume emission

TWI has recently developed a material, known as Barrikade ^TM, which offers a high level of fire resistance with no flame spread, no combustion and negligible emission of toxic fumes. It is ideal for use as both core and coating materials in a range of applications, such as bulkheads, firewalls and fire doors, since it is lightweight (200-300kg/m³) and unlikely to transfer significant heat in the event of a fire. It is expected that this material will attract great interest in the marine, offshore and building industries where fire protection and thermal insulation barriers are of critical importance for protecting people and/or equipment.